OBJECTIVE: To investigate the feasibility of the chitosan-collagen membrane (CCM) as a dermal substitute. METHODS: Fresh bovine tendo calcaneus collagen was dispersed in 0.5 mol/L acetic acid, co-precipitated with chitosan and lyophilized. Dry membranes were cross-linked in 0.05% glutaraldehyde for 24 hours. In vitro its degrading rate was measured by use of collagenase degrading test. The chitosan-collagen membrane was implanted to subcutaneous dorsal sites of SD rats. After implantation, histocompatibility, vascularity and degradation were observed in vivo. RESULTS: The chitosan-collagen membrane was yellowish, translucent, and porous. Pore size ranged 50-250 microns, and collagen fiber bundles were reticular arrangement in the membrane. It had slower degradation than pure collagen membrane by collagenase in vitro. Subcutaneous implantation test showed the minimal inflammation, good histocompatibility and earlier vascularization. The membrane degradation was slower in vivo. Eight weeks after implantation, organized collagen structure was retained. CONCLUSION: The chitosan-collagen membrane has better physical and biological properties, ideal histocompatibility, earlier vascularization and slower degradation. Therefore, It is an optimum substitute for dermal scaffold.
【摘要】 目的 探讨多功能外固定支架治疗老年股骨粗隆间骨折的疗效和优点。 方法 2007年7月-2009年10月，采用外固定架治疗28例老年股骨粗隆间骨折患者，其中男11例，女17例；年龄74~91岁，平均81岁。致伤原因:摔伤25例，交通事故伤3例。骨折按Evans分型:Ⅰ型1例，Ⅲ型15例，Ⅳ型12例。受伤至手术时间2~7 d。 结果 术后患者切口均Ⅰ期愈合，无延迟愈合及其他早期并发症发生。28例均获随访，随访时间5~14个月，平均9个月。X线片示骨折全部愈合，愈合时间11～24周，平均17周。无髋内翻和下肢短缩等并发症发生。术后3个月，采用Harris评分进行功能评价，优18例，良7例，差3例，优良率89.3%。出现轻度针道感染7例，中度5例，重度2例，针道感染率50%；合并糖尿病者2例出现中度针道感染，2例出现重度针道感染。重度者经局部换药、应用抗生素后愈合，后又反复出现，2~3个月取钉后愈合。无骨感染发生，患者均未出现褥疮，合并症无明显加重。 结论 外固定架治疗粗隆间骨折，手术创伤小，操作简便，符合生物力学原理，可以早期离床活动及早期骨折愈合。【Abstract】 Objective To explore the effectiveness and advantages of multifunctional external fixator for the treatment of femoral intertrochanteric fractures in the elderly patients. Methods Twenty-eight patients with femoral intertrochanteric fractures including 11 males and 17 females receiving external fixator treatment between July 2007 and October 2009 were enrolled in this study. Their age ranged from 74 to 91 years old with the average to be 81 years. Twenty-five patients had the disease because of ground falls, and the other 3 were due to traffic accidents. Based on the Evans Type classification, there were 1 Type-Ⅰ case, 15 Type-Ⅲ cases, and 12 Type-Ⅳ cases. The time between injury and surgery was ranged from 2 to 7 days. Results All incisions of the patients healed during phase Ⅰ without delayed healing or other early complications. Follow-up was done to all the patients for 5 to 14 months, averaging 9 months. X-ray showed all fractures healed, and the healing time ranged from 11 to 24 weeks with an average of 17 weeks. No varus or leg shortening or other complications occurred. Three months after surgery, based on the Harris hip score for functional evaluation, there were 18 excellent cases, 7 good cases and 3 poor cases with a excellent and good rate of 89.3%. Mild pin tract infection was detected in 7 patients, moderate in 5, and severe in 2 with a total pin tract infection rate of 50%. Two patients with diabetes suffering from severe pin tract infection recovered by local medication and antibiotics, but the infection reoccurred repeatedly till the healing nails were taken. No bone infection of ulcers occurred, and the existing complications were not aggravated. Conclusion Treatment of intertrochanteric fractures with multifunctional external fixator is minimally invasive, simple, and consistent with biomechanical principles, which can promote early activities out of bed and early fracture healing for the patients.
Objective To evaluate changes of local flow field following implantation of a designed iliac venous stent. Methods Anin vitro physical model with iliocava junction was established. A modified iliac venous stent was implanted into one side and a conventional stent into the other side. The bilateral local flow fileds following implantation of stents were measured by using particle image velocimetry. Results The results of particle image velocimetry testing revealed that the main flow orientation was shifted to the right side and the region of slowly local flow was observed after implantation of conventional iliac venous stent. However, no evident changes were noted in the local flow field and no whirling flow was detected following implantation of the designed iliac venous stent. Conclusion Conventional stent is implanted into iliac vein by using a traditional technique and stent is proximal to heart and covers opening of contralateral iliac vein, which exerts certain influence upon local flow field. Local flow field has no obvious change following implantation of a designed iliac venous stent.
ObjectiveTo investigate the improvement of visceral arterial blood supply after thoracic endovascular aortic repair (TEVAR) for patients with Stanford type B aortic dissection (AD). MethodsWe retrospectively analyzed clinical data of 35 patients with Stanford type B AD undergoing TEVAR in Mianyang Central Hospital from January 2013 to March 2014. There were 30 male and 5 female patients with their age of 45-82(62.5±10.0) years. Among the 140 main visceral arteries (celiac artery, superior mesenteric artery, left and right renal arteries) of the 35 patients, blood supply of 79 arteries were compromised, including 36 arteries with stenosis and blood supply via the true lumen, 18 arteries with blood supply via both true and false lumen, 18 arteries with blood supply via the false lumen, and 7 arteries without blood supply. Improvement of blood supply of main visceral arteries was analyzed. ResultsAll the operations were successfully performed without in-hospital death. Operation time was 97.8 (68-147) minutes, length of ICU stay was 12-34 h, and length of hospital stay was 10-21 days. None of the patients had cerebral infarction, acute renal failure, AD rupture or stent migration after TEVAR. Blood supply of the compromised visceral arteries showed improvement in various degrees. ConclusionFor the treatment of Stanford type B AD, TEVAR can not only successfully block the rupture of AD, but also improve blood supply of main visceral arteries, avoid or reduce the complications resulting from compromised visceral arterial blood supply and visceral ischemia.
New biodegradable intravascular stent can reduce risk of foreign bodies retained, thus, it is widely concerned and some of the products have been introduced into the clinic. However, the characteristic of biodegradable may lead to more safety concerns associated with thrombosis. To ensure the safety, the thrombus formation experiment in vivo needs to be carefully designed and evaluated based on GB/T 16886.4 standard, but current standard do not provide explicit testing and evaluating methods. Establishing animal model with experimental pigs, the study compares biodegradable coronary stents and metal stents by simulating clinical implantation in vivo on the thrombus formation in the implanting process, and after the short-term and long-term implantation. The evaluation methods include gross observation, digital subtraction angiography intraoperative analysis, optical coherence tomography analysis, scanning electron microscopy and so on. The results show that combining these methods could comprehensively evaluate the whole process of the thrombus formation from the beginning of implantation to the end of preclinical animal experiments, so that, it may better predict the clinical thrombosis risk, and the selection of the control was very important. The study tries to use the comparison examples of thrombosis on the new medical instrument to provide the clue for thrombosis evaluation in vivo on similar instruments and show the methodology on the preclinical evaluation.
ObjectiveTo investigate the efficacy and safety of laparoscopic cholecystectomy and common bile duct exploration(LCBDE) with biliary stent drainage or T tube drainage. MethodsThe clinical data of 68 cases of gallbladder and bile duct stones with the LCBDE by the same surgeon in our hospital from June 2008 to June 2013 were retrospectively analyzed. Twenty-two patients were treated with LCBDE and biliary stent drainage(stent drainage group), 46 patients were treated with LCBDE and T tube drainage(T tube drainage group). ResultsThe operation were successfully completed of 2 groups. The anal exhaust time, peritoneal drainage time, postoperative hospitalization time, and hospital expenses in stent drainage group were shorter or less than thoes T tube drainage group(P < 0.05). There were no significant difference in the operative time, postoperative bilirubin level, and incidences of postoperative complications between the two groups(P > 0.05). ConclusionsThe stent drainage and T tube drainage after LCBDE has its own indications. Laparoscopic common bile duct exploration and biliary stent drainage is superior to the laparo-scopic common bile duct exploration and T tube drainage.
Objective To evaluate the feasibility of X-ray guided access to the extrahepatic segment of the main portal vein (PV) to create a transjugular extrahepatic portacaval shunt (TEPS). Methods 5F pigtail catheter was inserted into the main PV as target catheter by percutaneous transhepatic path under ultrasound guidance. The RUPS-100 puncture system was inserted into the inferior vena cava (IVC) by transjugular path under ultrasound guidance. Fluency covered stent was deployed to create the extrahepatic portacaval shunt after puncturing the target catheter from the IVC under the X-ray guidance, then shunt venography was performed. Enhanced CT of the abdomen helped identify and quantify the patency of the shunt and the presence of hemoperitoneum. Results The extrahepatic portacaval shunts were created successfully by only 1 puncture in 6 pigs. No extravasation was observed in shunt venography. One pig died of anesthesia on the day of operation. The extrahepatic portacaval shunts were failed in 2 pigs 3 days after the operation (one was occluded and the other one was narrowed by 80%). The extrahepatic portacaval shunts were occluded 2 weeks after the operation in the remaining 3 pigs. The shunts were out of the liver and no hemoperitoneum was identified at necropsy in the 6 pigs. Conclusion TEPS is technically safe and feasible under the X-ray guidance.
Objective To study the feasibility of using mice marrow stromal stem cells(MSCs) as seed cells for tissue engineering cartilage to embed the seed cells in acellular cartilage matrix of human auricle. Methods Acellular cartilage matrix was made from human auricle cartilage. The MSCs were isolated from the nucleated cells fraction of mice marrow by centrifuge.The MSCs were embedded in acellular cartilage matrix. After 10 day’s combined culture, the specimens were observed with optical and electrical microscope.Results The MSCs could well proliferate in the acellular cartilage matrix. The cells were not well-distributed in acellular cartilage matrix. There were more cells in the peripheral part of the matrix than in the central part of the matrix. Most of the cells were in cartilaginous lacunae. There were 1 or 2 cells in every cartilaginous lacunae.Conclusion The MSCs can be used as seed cells of tissue engineering and can well proliferate in the acellular cartilage matrix and become tissue engineering cartilage.
Objective To compare the difference of preparing the acellular larynx scaffold between perfusion method and immersion method, and find better way to make acellular larynx scaffold for tissue engineering. Methods Twenty 6-month-old male New Zealand rabbits, weighing 2.0-2.5 kg, were divided into perfusion group (n=10) and immersion group (n=10) at random. All the larynxes were excised in a sterile fashion. The acellular larynx scaffold was obtained by perfusionmethod and immersion method respectively, and then comparative examinations were performed by the macroscopicview, histological view, scanning electron microscope (SEM), cartilage vital ity assay and toluidine blue staining. ResultsMacroscopic view showed that the larynxes perfused by sodium dodecyl sulphate (SDS) became transparent after 2 hoursof perfusion, but the larynxes immersed by SDS over 16 hours still appeared pink-white. Histology and SEM indicated thatcompared with immersion group, perfusion group showed better acellular effect, more ventages and collagen fibers wereretained, no intact cell or nuclei remained in acellular matrix and chondrocytes were still survival. The porosity was 85.39% ± 3.16% in perfusion group and 34.72% ± 4.51% in immersion group, showing significant difference (P lt; 0.01). The chondrocyte vital ity rate of perfusion group (86.93% ± 1.52%) was higher than that of immersion group (77.73% ± 1.66%), showing significant difference (P lt; 0.01). Toluidine blue staining showed that the chondrocyte heterochromaty was ber in perfusion group than that in immersion group. Conclusion Compared with immersion method, perfusion method is a better way to construct acellular larynx scaffold because it can achieve better acellular effect and retain chondrocyte vital ity at the greatest extent in the acellular larynx scaffold.
Abstract: Objective To examine the cell viability and hemodynamic functions of the stented homograft valves preserved in liquid nitrogen. Methods Cell viability of the stented homograft valve preserved in liquid nitrogen after 3 months of preservation (experimental group，n=6) was examined using flow cytometer. Fresh homografts served as control group (n=6). We prepared three sorts of stented homograft valve(21#, 23#, 25#) preserved by liquid nitrogen. In vitro pulsatile flow tests were performed on valves of two groups. Effective opening area EOA),transvalve pressure gradient and regurgitation ratio were recorded at various flow volume, and compare with Perfect bioprosthetic valve. Results The results revealed that the death ratio of endothelial cell was 10.24%±1.71% in the experimental group, and 9.09%±2.72% in the control group (P=0.441). The death ratio of smooth muscle cell was 8.76%±1.82% in the experimental group, and 7.84%±0.59% (P=0.178) in the control group. The death ratio of total cell was 8.79%±1.44% in the experimental group, and 7.40%±0.49% in the control group (P=0.072). There were no significantly differences between two groups. The transvalve pressure gradient of two groups of valve depended on the flow volume, and increased with the flow volume increasing. The transvalve pressure gradient of the stented homograft valve was higher than that of Perfect valve. Regurgitation ratio of the stented homograft valve was bigger than Perfect valve’s. EOA had an increasing character when flow volume increased. EOA of the stented homograft valve was smaller than that of Perfect valve’s. Conclusion Liquid nitrogen can offer the benefit of cell viability of the stented homograft bioprosthetic valves. The stented homograft valve has salisfactory hemodynamic functions.